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LCD question

Sorry if this is off-topic. If it is, I'd appreciate a pointer as to where to look.

I am looking at hooking up a 7" LCD panel to an embedded Linux computer.

Besides the frustration of realizing that no one really makes a standard interface for these panels, (LVDS, digital, 8 bit, etc...) , what I find far worse is the backlight situation.

How, exactly, am I supposed to light up the panel?

I understand the LCD controller gets its power from the interface connector one way or the other. The SBCs in general supply enough current to power the LCD controller.

Now, how do I power the backlight? SBCs all have various "backlight" outputs on them, generally including things like "backlight enable" and and 0-5V analog brightness signal, but no LED juice.

OK, how do I generate the ~10V at ~250mA ?? There seem to be no standard controllers for this.

EIther I find datasheets for driver ICs, or LED lighting controllers with far too much current output. And if they are dimmable, they use

0-10V. Useless.

The few controller boards I've found like the Atmel are so expensive as to be stupid. 110$ for a small PCB with a chip and a coil? Come on Avnet....

And not to mention you're on your own as far as cables go. How do I connect to this stuff??

And one last thing. SBCs are all touted as being low power, yet no one makes 12V battery-based 5V supplies??? If it's low-power, and all I can find are wall warts, who cares? It can suck 300W for all I care.

So I'm missing something here. Are LCDs supposed to be difficult to operate like this? And who makes 5V supplies that run off batteries?

Am I supposed to build these items after buying all the rest???

Reply to
a7yvm109gf5d1
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I guess you need an ATX power supply. Had you considered one like this?

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Regards, Allan

Reply to
Allan Herriman

?

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No, I just need 5V. It stuns me that companies make these single voltage SBCs but no one makes power supplies for them. It's not a ATX power supply that I need. And I still can't light up the backlight. What a bizarre world.

Reply to
a7yvm109gf5d1

Beg to differ. Very quick look on Amazon revealed several 12V - 5V DC converters. For the 10V you might need to do some DIY, but I think it would just need a 10V LDO voltage regulator.

Cabling should not be an insurmountable issue, you just need some simple tools.

The commercial world very much works on supply and demand, which may sometimes produce counterintuitive results, which you might consider bizarre, but I would regard as normal.

Reply to
Bob

verters. For the 10V you might need to do some DIY, but I think it would ju= st need a 10V LDO voltage regulator.

tools.

times produce

egard as

It's normal for companies to design super low power SBCs and then you have to kludge together a power supply for it? It's normal for companies to supply LCD panels with no way to power the backlight?

So you have a system with a professionally built SBC with a 1.6GHz Atom that runs Linux, powered by a contraption? The LCD needs a constant current source that can be dimmed by a 0-5V analog signal, yet there is no such device anywhere. This is normal?

There's no demand to, you know, light up the LCD panel????

I'm missing something here.

And I can't find anything on Amazon. It has no search filtering. I'm not browing the 500000 hits for "dc-dc" one by one.

I have seen no power supply that takes 10-13V DC in and gives a regulated 5V 2A out.

Reply to
a7yvm109gf5d1

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Reply to
hamilton

e:

onverters. For the 10V you might need to do some DIY, but I think it would = just need a 10V LDO voltage regulator.

e tools.

metimes produce

regard as

take a laptop apart and you'll probably find it has small pcb, in the screen part, with the driver for the backlight

I guess the expectation is tat anyone buy bare panels will be putting them i boxes so they want to do their own drivers

something like this?

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HD/dp/B003G8OVNA

-Lasse

Reply to
langwadt

OK, I think the problem is you have bought the wrong product. SBCs are designed for integrators and tinkerers who know what do with them, or are at least willing to learn. It sounds like you wanted a ready to go system.

I think what you call "kludging" is what we call "engineering", i.e. integrating parts to create a particular solution, if necessary developing new stuff.

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Reply to
Bob

car-P...

Well, no one except for Vicor and all of their competitors:

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--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com
Reply to
Tim Wescott

l
e

Oh yes, 38V to 45V input. Now I just need a battery powered 40V supply! Brilliant!

Let me guess: none of these products are stocked by any of the big distributors, or if they are, they're 500$ each.

Reply to
a7yvm109gf5d1

signed for integrators and tinkerers who know what do with them, or are at = least willing to learn. It sounds like you wanted a ready to go system.

grating parts to create a particular solution, if necessary developing new = stuff.

Again. Why supply LCDs if you don't supply the backlight controller? The same companies supply touch controllers.

Why not a backlight controller? Makes no sense. SBCs aren't designed for "tinkerers".

You guys are just making excuses for a situation that's absurd.

Reply to
a7yvm109gf5d1

..

Ooooh aren't you a clever boy? Yet still no real products. You spend

300-400$ for a SBC, then what? You get a cheap kludge, or some off- brand mystery part to power it?

Clever! Clever!

BTW, "battery" doesn't mean "car".

Reply to
a7yvm109gf5d1

You paid $400 for an SBC and you don't know how to wire a plug? Salesman saw you coming!

To be quite honest, your attitude and skills are not suited to this endeavour. I suggest you find an easier hobby or somewhere else to whine.

I guess this sort of thing is a product of a consumer generation that just expects to buy ready made solutions, made cheaply in China. It is kinda sad that people don't seem to have any idea about making things any more.

Reply to
Bob

Ploink

Reply to
hamilton

If finding/specifying a power supply is in your 'too hard' box, perhaps it is time to consider a change of profession ?

{ Digikey popped out 29 suggestions in a few mouse clicks.... }

Reply to
Jim Granville

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Mark DeArman

Reply to
Mac Decman

Looks like linear tech has the best selection of parts.

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Reply to
Mac Decman

Computer-

DigiKey has seven pages, in stock, some with prices in the single digits.

Can't you do your own searches?

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com
Reply to
Tim Wescott

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